120 BULLETIN 91, "UNITED STATES NATIONAL MUSEUM. 



LITTORINA AFRICANA TRYPHENA, new subspecies. 

 Plate 38, fig. 6. 



This subspecies of L. africana is of similar coloration as africana, 

 but always more slender, in fact, pupoid in shape. The type and 

 another specimen, Cat. No. 187091, U.S.N.M., come from Port Alfred 

 (Coll. No. 635). The type has 4£ whorls, and measures: Length, 7 

 mm.; diameter, 4.6 mm^ Four additional lots are in the collection 

 of the United States National Museum from Port Alfred. Cat. No. 

 187090, one specimen (Coll. No. 634). Cat. No. 250509, two speci- 

 mens (Coll. No. 1382). Cat. No. 250510, one specimen (Coll. No. 

 1383). Cat. No. 250511, one specimen (Coll. No. 1384). 



LITTORINA KNYSNAENSIS Krauss. 



Cat. No. 116, U.S.N. M., six specimens collected by William Stimp- 

 son on the North Pacific Exploring Expedition at Cape of Good Hope. 

 Cat. No. 21810, U.S.N.M., one specimen collected at Algoa Bay by 

 Dunker. Cat. No. 98054, U.S.N.M., 84 specimens from the Albany 

 Museum, which were collected at the mouth of Bushmans River. 

 Cat. No. 186810, U.S.N.M., four specimens from Port Alfred (Coll. 

 No. 176). Cat. No. 18795, U.S.N.M., five specimens collected by 

 William Stimpson on the North Pacific Exploring Expedition at Port 

 Elizabeth. Cat. No. 31850, U.S.N.M., five specimens from the Cape 

 of Good Hope. 



LITTORINA AHENEA Reeve. 



Cat. No. 187089, U.S.N.M., one specimen from Port Alfred (Coll. 

 No. 632). 



Genus TECTARIUS Valenciennes. 



TECTARIUS NATALENSIS Krauss. 



Cat. No. 18823, U.S.N.M., three specimens from Natal. 



Genus CITHNA A. Adams. 

 CITHNA AFRICANA, new species. 



Plate 21, fig. 5. 



Shell very minute, subglobular, moderately, deeply umbilicated, 

 semitranslucent. Nuclear whorls about one and a third, scarcely 

 differentiated from the rest of the turns. All the whorls well rounded, 

 without sculpture, separated by a moderately constricted suture. 

 Periphery and base of the last whorl well rounded, the latter mod- 

 erately umbilicated, the outer edge of the umbilicus angulated. 

 Aperture oval; outer lip rather thick, thinning toward the edge; the 

 inner lip oblique, joined with a thin callus on the parietal wall, which 

 renders the peritreme complete. 



The type, Cat. No. 250498, U.S.N.M., comes from Port Alfred (Coll. 

 No. 1371). It has almost three postnuclear whorls, and measures: 

 Length, 0.7 mm.; diameter, 0.7 mm. 



